/*
 * Copyright 2002-2012 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.remoting.support;

import java.lang.reflect.Method;

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.util.ClassUtils;

/**
 * AOP Alliance MethodInterceptor for tracing remote invocations.
 * Automatically applied by RemoteExporter and its subclasses.
 *
 * <p>Logs an incoming remote call as well as the finished processing of a remote call
 * at DEBUG level. If the processing of a remote call results in a checked exception,
 * the exception will get logged at INFO level; if it results in an unchecked
 * exception (or error), the exception will get logged at WARN level.
 *
 * <p>The logging of exceptions is particularly useful to save the stacktrace
 * information on the server-side rather than just propagating the exception
 * to the client (who might or might not log it properly).
 *
 * @author Juergen Hoeller
 * @see RemoteExporter#setRegisterTraceInterceptor
 * @see RemoteExporter#getProxyForService
 * @since 1.2
 */
public class RemoteInvocationTraceInterceptor implements MethodInterceptor {

    protected static final Log logger = LogFactory.getLog(RemoteInvocationTraceInterceptor.class);

    private final String exporterNameClause;


    /**
     * Create a new RemoteInvocationTraceInterceptor.
     */
    public RemoteInvocationTraceInterceptor() {
        this.exporterNameClause = "";
    }

    /**
     * Create a new RemoteInvocationTraceInterceptor.
     *
     * @param exporterName the name of the remote exporter
     * (to be used as context information in log messages)
     */
    public RemoteInvocationTraceInterceptor(String exporterName) {
        this.exporterNameClause = exporterName + " ";
    }


    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        Method method = invocation.getMethod();
        if (logger.isDebugEnabled()) {
            logger.debug("Incoming " + this.exporterNameClause + "remote call: " +
                    ClassUtils.getQualifiedMethodName(method));
        }
        try {
            Object retVal = invocation.proceed();
            if (logger.isDebugEnabled()) {
                logger.debug("Finished processing of " + this.exporterNameClause + "remote call: " +
                        ClassUtils.getQualifiedMethodName(method));
            }
            return retVal;
        } catch (Throwable ex) {
            if (ex instanceof RuntimeException || ex instanceof Error) {
                if (logger.isWarnEnabled()) {
                    logger.warn(
                            "Processing of " + this.exporterNameClause + "remote call resulted in fatal exception: " +
                                    ClassUtils.getQualifiedMethodName(method), ex);
                }
            } else {
                if (logger.isInfoEnabled()) {
                    logger.info("Processing of " + this.exporterNameClause + "remote call resulted in exception: " +
                            ClassUtils.getQualifiedMethodName(method), ex);
                }
            }
            throw ex;
        }
    }

}
